webr-cells do not get rendered in live-revealjs when the document also contains r-cells

[ute]

Mixing {webr} and {r} code cells works as expected when the format is live-html, but not when the format is live-revealjs. Maybe this is related to #47 ?

Here is a mwe:

---
title: "MWE live webr and r code cells don't mix in revealjs"
format: live-revealjs
# format: live-html
---

## Mixing both

An R code cell

```{r}
hist(rnorm(2000))
```

and an interactive code cell

```{webr}
hist(rnorm(2000))
```
go well together in live-html